Hi Fishdance,
First of all, let me say that I really appreciate the reply since I'm not too familiar with all the technical and scientific approach. So any insights is really helpful. As for the technique that you described:
1. To keep 2 arowana in the same tank is usually a suicide act since they would fight till death. It is well known among so called Arowana 'experts' that if you MUST keep more than 1 in the same tank, the number should be greater than 4. This way, they still fight but not fatal.
2. I'm not too familiar with taking blood sample and will look into it. But have found out that DNA testing is very costly.
3. I haven't heard of this technique either (canulation for eggs). Can you please describe it in more detail? is the equipment readily available for purchase?
4. "Squeeze & milk", although it is very effective for certain species, this is taboo according to Arowana 'experts'. The reason being if you squeeze too hard and the one that you squeeze happens to be the female fish, it will die because of the egg burst. And nobody bothers to try
this method since once upon a time, a few dare souls tried and their fishes died (according to the legend that I heard when I first started

). And to prove otherwise would be a huge bet considering the price of a matured Arowana (not to mention all the immature eggs inside.. who would dare to gamble?)
Once again, I really appreciate your effort to post them. I would be glad to show you around (the farm and the city) if you come to visit West Kalimantan.